1. Field of the Invention
The present invention relates to a fuel reforming system for reforming fuel (e.g., butane) and producing reformed gas rich in hydrogen, and fuel cell system including the same, and more particularly, to a fuel reforming system and a fuel cell system including the same, in which a heat source is movable to provide heat energy to a reaction region for producing reformed gas with a hydrogen base.
2. Discussion of Related Art
A fuel cell system generates electric energy through a chemical reaction between oxygen and hydrogen or between oxygen and reformed gas (rich in hydrogen). The reformed gas is obtained from a fuel containing hydrogen that includes an alcoholic fuel such as methanol, ethanol, etc.; a hydro-carbonaceous fuel such as methane, propane, butane, etc.; or a natural gas fuel such as liquefied natural gas, etc.
The fuel cell system can be classified into a phosphoric acid fuel cell (PAFC), a molten carbon fuel cell (MCFC), a solid oxide fuel cell (SOFC), a polymer electrolyte membrane fuel cell (PEMFC), an alkaline fuel cell (AFC), etc., according to kinds of electrolytes used. Further, the fuel cell system can be applied to various fields such as mobile devices, transportation devices, distributed power sources, etc. according to kinds of fuels, driving temperatures, output ranges, etc.
Recently, a fuel cell system has been developed that uses a butane fuel contained in a standard portable container on the market as a fuel source.
Referring to FIG. 6, an example of such a fuel cell system is disclosed in U.S. Pat. No. 6,183,895. Here, the fuel cell system includes fuel supplying device 12 having a portable pressure container 1 containing butane gas and parts 2 (pressure container receiver) and 3 (evaporator) adapted to adjust the amount of butane gas and to control flux of the butane gas, a reformer 4 using a portion of the butane gas contained in the pressure container 1 as fuel gas of a combustor and reacting another portion of the butane gas with water to produce reformed gas containing hydrogen-rich gas, a carbon monoxide (CO) eliminator 5 adapted to decrease the concentration of carbon monoxide in the reformed gas, a fuel cell 6 using hydrogen in the reformed gas and oxygen in air to generate electricity, and an inverter 21 carrying out stable conversion from direct current to direct current or from direct current to alternating current. However, in the reformer 4 of this fuel cell system, a reaction region of the reformer 4 for obtaining the reformed gas rich in hydrogen from the butane gas is not effectively heated, resulting in a relatively low reforming efficiency.
Referring to FIG. 7, a reformer is disclosed in U.S. Pat. No. 6,413,479. Here, the reformer includes a raw material reformer part that directly receives reaction heat from a heat source so as to steam-reform a reforming fuel to thus produce reformed gas rich in hydrogen, and a shift reaction part and a carbon monoxide (CO) oxidation part, which are indirectly heated by electric heat transferred from the heat source. However, in this reformer, the shift reaction part is indirectly heated, so that it takes a relatively long time to supply sufficient heat needed for reaction processes.